What primary technology is used in the Data Link layer for sending frames?

The primary technology used in the Data Link layer for sending frames is MAC addresses. At this layer, the focus is on the physical addressing of devices within the same local area network (LAN). MAC addresses are unique identifiers assigned to network interfaces for communications at the data link layer. This allows for the proper identification of devices that are sending and receiving frames across the network.

The Data Link layer utilizes these MAC addresses to ensure that data frames are delivered to the correct destination device on the local network. When a frame is transmitted, it includes the MAC address of the source device as well as the MAC address of the destination device, which enables switches and network devices to determine where to send the frames.

While fiber optics, IP addresses, and wireless protocols play important roles in networking, they belong to different layers of the OSI model. Fiber optics are a medium for transmitting data (typically used in the Physical layer); IP addresses operate at the Network layer for routing packets across different networks; and wireless protocols are methods enabling communication using radio signals, which can sit at various layers, depending on their implementation. Therefore, MAC addresses are integral to the functioning of the Data Link layer, making them the correct answer in this context.